Geologist Ascends Peaks and Dives to the Ocean Floor, Looking for Secrets of Earth's
Crust

Peter Kelemen, who was recently appointed
Arthur Storke Memorial Professor of Geochemistry in the Department
of Earth and Environmental Sciences at Columbia University, shown here
in East Greenland, 2000, scoping out the East Face of Ejnar Mikkelsen's
Fjeld.

Says
Keleman of this photo, "This mountain is composed of 'flood
basalt' lava flows, which erupted to form a seven-kilometer-thick
pile of volcanic rocks in less than one million years, about 56
million years ago, just before the opening of the North Atlantic.
Supported by the Danish Lithosphere Centre, Stefan Bernstein
(now at the Greenland Geological Survey) and I camped here,
50 km from the coast and a much longer way to the nearest other
person, for ten days in the summer of 2000.

"In
1995, Stefan and I had found fragments of the Earth's upper mantle,
dating to about 3 billion years ago, that were carried to the
surface in a dike-feeding lava flows. These are the only mantle
samples from East Greenland, and among very few examples of
mantle from the ancient Greenland craton, which contains the
oldest rocks on Earth.

"We projected the trend of dikes that
hosted mantle fragments inland, and chose this place to look
for more fragments five years later, travelling on skis along
the edge of the huge Kronborg Glacier. And we found
more mantle samples!" Photo by Stefan Bernstein

As a geologist, Peter Kelemen has ascended to
7,500 meters on a Himalayan peak and plummeted into the Atlantic
to 5,500 meters. From 1981 to 1991, he worked as a consultant on
mineral exploration projects where the terrain was too steep for
average geologists. He has traveled via snowmobile, helicopter
and climbing rope, all in the pursuit of secrets of the Earth's
crust.

In the Himalayas, he studied the process of
mountain building at the collision of India and Asia, where the
enormous peak of Gasherbrum IV rises up 8,000 meters — a
perfect location to study a vast range of elevations. He has also
done research in Oman, where a block of the Earth's crust (called
an "ophiolite")
the size of Massachusetts has been thrust up on land. Says
Kelemen, who was recently appointed the Arthur Storke Memorial
Professor of Geochemistry in the Department of Earth and Environmental
Sciences, "The
Oman ophiolite offers a view of the internal geometry of oceanic
plates that is unmatched by any sampling or imaging technique at
sea."

The melt flow beneath volcanoes —"the
plumbing systems of volcanoes," as Kelemen puts it — is
another area of study for him. Because melt is highly reactive,
focused melt migration leaves visible traces. Studying this process
provides clues to how reactive porous flow of other substances,
for example in oil fields, might be organized. Kelemen plans someday
to extend his studies to fluid migration within glaciers. "With
glaciers the drainage morphology is very similar to that in the
mantle beneath volcanoes," he says. "The benefit is we
can study an active system versus what may have happened hundreds
of millions of years ago in the upper mantle. There is lot of fairly
basic physics in melt migration that is analogous to other kinds
of fluid migration."

“By studying melt migration processes,” Kelemen says, “scientists
can learn how geological systems organize themselves. It also may
provide answers to how much energy is emitted from the Earth's
interior to the hydrosphere, and what the spatial distribution
of that energy emission is — subjects of much debate among scientists.”

For summer 2005, Kelemen, through funding from
the National Science Foundation, has planned a research trip to
the western end of the Aleutian volcanic chain, an area he has
studied for ten years but has never visited. There, in the 1960's,
a lava sample was recovered from the seafloor that has a very similar
composition to the ancient continental crust. Kelemen plans to
obtain more of these samples by examining the catch from a metal
bag about ten feet in diameter that will be dragged along the flanks
of submarine volcanoes on the seafloor. He hopes his research will
provide information on how the continental crust was formed.

Kelemen and his colleagues Dave Scholl and Gene
Yogodzinsk also plan to create a more accurate bathymetric map. "There
are probably hundreds of volcanoes in that area that don't exist
on maps," he says. "An active volcano in the western
Aleutians that comes within 115 meters of the ocean surface was
just discovered and mapped in 2002-2003." (The mapping was
directed by Jennifer Reynolds, a Lamont-Doherty Earth Observatory
alumnus; more information is at http://www.sfos.uaf.edu/news/2003/0811volcano.html.)

Peter Kelemen

Kelemen, who came to Columbia University after
15 years at the Woods Hole Oceanographic Institution, joined the
Lamont-Doherty Earth Observatory and DEES this summer. This past
spring, he was elected a Fellow of the American Geophysical Union.
In addition to his research, Kelemen is co-teaching Introduction
to Earth Sciences 1 with John Mutter, Deputy Director of the Earth
Institute, who has taught the class for the past 10 years.

Last fall, Kelemen and his colleague Greg Hirth
in Woods Hole initiated an unusual new field course for graduate
students. They spent 10 days at sites where the Earth's
mantle has been thrust up on land and exposed. During this project-oriented
graduate field class, students mapped and sampled a small area,
and then Kelemen expedited sample analyses, allowing students
to spend the semester learning techniques and interpreting their
results for a final project. Last fall, Kelemen took students to
northern California, though the locations vary.

As for exploring rocks more than 5,000 meters
below sea level in a submersible, Keleman says, "The viewing
window is so small. I'd rather combine sea-going observations with
field work someplace where I can actually see the rocks."

The Lamont-Doherty Earth Observatory, a member
of the Earth Institute at Columbia University, is one of the world's
leading research centers examining the planet from its core to
its atmosphere, across every continent and every ocean. From global
climate change to earthquakes, volcanoes, environmental hazards
and beyond, Observatory scientists provide the basic knowledge
of Earth systems needed to inform the future health and habitability
of our planet.

The Earth Institute at Columbia University is among the
world's leading academic centers for the integrated study of Earth,
its environment, and society. The Earth Institute builds upon excellence
in the core disciplines—earth sciences, biological sciences, engineering
sciences, social sciences and health sciences—and stresses cross-disciplinary
approaches to complex problems. Through its research, training and global
partnerships, it mobilizes science and technology to advance sustainable
development, while placing special emphasis on the needs of the world's
poor.